1. Technical Field of the Invention
The present invention relates to a technology for analyzing and audibly outputting a sound generated by a virtual sound generator.
2. Description of the Related Art
Conventional acoustic wave simulation enables accurate reproduction of a real acoustic phenomenon when the model of a target object, a target space, a constraint condition, or the like of the simulation is simple (for example, when a sound generated by striking a metal or wood panel is simulated). However, when the target object of the simulation is a sound generator having complicated conditions, the result (solution) of the simulation is degraded in accuracy and the quantitative acoustic characteristics of the simulation significantly differ from those of a real acoustic phenomenon although the qualitative acoustic characteristics thereof are generally similar to those of the real acoustic phenomenon.
The following technologies have been suggested to overcome these problems.
Patent Reference 1 has disclosed a technology in which acoustic characteristics of a molded product are analyzed by calculating local physical property data of the molded product and assigning the physical property data to each corresponding local region thereof, thereby achieving accurate analysis of acoustic characteristics.
Patent Reference 2 has disclosed a technology in which sound pressure spectrum data of vibration and acoustic analysis is converted into a time-series waveform, and the waveform is then reproduced through a speaker to estimate the waveform.
Patent Reference 3 has disclosed a technology in which physical characteristics of a sound absorbing/insulating material are calculated using theoretical values or measured values when a relatively large sound field is analyzed.
[Patent Reference 1] Japanese Patent Application Publication No. 2003-090758
[Patent Reference 2] Japanese Patent Application Publication No. 2005-308726
[Patent Reference 3] Japanese Patent Application Publication No. 2006-065466
In the technologies of Patent References 1 and 2, it is difficult to accurately set various input conditions that are set for analysis and that include a constraint condition, a mount condition, and a boundary condition such as a sound absorbing condition of a structure, a vibration condition of a sound source or a vibrating body, and a vibration attenuation coefficient of a structure. Errors in such input conditions cause a reduction in simulation accuracy.
In addition, if the simulation result (solution) is directly used to reproduce a sound through a speaker, the reproduced sound has a significant aural difference from a sound generated by a real object, thus failing to achieve appropriate sound estimation.
Further, when a sound is reproduced through a speaker using data of only a limited frequency band with high accuracy in simulation, i.e., when a sound is reproduced with a limited band, the reproduced sound also has a significant aural difference from a sound generated by a real object, thus failing to achieve appropriate sound estimation.
Furthermore, the technology of Patent Reference 3 also has limitations in accuracy of analysis in association with the validity of a logical model or the matching thereof with a target model when theoretical values are used, and in association with actual measurement under an ideal condition of a single substance rather than under a real sound field when measured values are used.